1. Field of the Invention
The present invention relates to a biopsy needle for extracting a tissue sample from a biopsy region in an object to be examined, a sample extracting unit and a biopsy apparatus incorporating such a biopsy needle, and a method of controlling such a biopsy needle.
2. Description of the Related Art
Heretofore, doctors have widely performed a biopsy procedure for inserting a biopsy needle into an object to be examined, e.g., a living body such as a human body, and extracting a tissue sample from a biopsy region in the object. Generally, in order to reduce the physical burden on the object, it is desirable to insert the biopsy needle at an appropriate position for reliably and accurately extracting a tissue sample from the biopsy region. Accordingly, it has been customary in biopsy to carry out a stereoscopic image capturing process in which a radiation is applied to an object to be examined, and a stereoscopic image of the object is acquired, and then to calculate a three-dimensional position of the biopsy region from the stereoscopic image, before the biopsy procedure.
However, even if the three-dimensional position of the biopsy region is accurately grasped, in the case where the biopsy needle is inserted into the object, the needle may deviate from the desired puncture path for some reasons, e.g., an interference with a blood vessel in the object. As a result, the inserted biopsy needle does not follow the desired puncture path, and then the positional relationship, i.e., distance and direction relationship, between the biopsy region from which a tissue sample is to be extracted and the opening of the biopsy needle may deviate from an expected value. To solve the problem, there have been proposed various technologies for aspirating and sampling an appropriate amount of tissue from a biopsy region through a biopsy needle without the need for inserting the biopsy needle again.
Japanese Laid-Open Patent Publication No. 2007-520253 (PCT) discloses a bone marrow sampling apparatus having a double-tube structure which includes an outer tube having a plurality of aspiration holes defined therein and an inner tube having at least one hole defined therein. The bone marrow sampling apparatus is capable of adjusting the flow rate of a spinal fluid flowing through the double-tube structure by selectively moving the outer and inner tubes relatively to each other, or specifically translating and/or rotating the inner tube with respect to the outer tube. For example, the flow rate of the spinal fluid is adjusted by increasing or reducing the number of aspiration holes.